A certain fluorine-containing silane compound is known to be able to provide excellent water-repellency, oil-repellency, antifouling property, or the like when it is used on a surface treatment of a base material. A layer (hereinafter, referred to as a “surface-treating layer”) formed from the surface-treating agent comprising a fluorine-containing silane compound is applied to various base materials such as a glass, a plastic, a fiber and a building material as a so-called functional thin film.
As such fluorine-containing silane compound, a perfluoropolyether group containing silane compound which has a perfluoropolyether group in its molecular main chain and a hydrolyzable group bonding to a Si atom in its molecular terminal or its terminal portion is known. For example, Patent Literature 1 describes a fluoro-containing silane compound comprising a molecular main chain having a perfluoropolyether group and a plurality of polyethylene chains having a Si atom having a hydrolyzable group in a side chain of the polyethylene chains.